Karaolis D K, Lan R, Reeves P R
Department of Microbiology, University of Sydney, New South Wales, Australia.
J Bacteriol. 1994 Oct;176(20):6199-206. doi: 10.1128/jb.176.20.6199-6206.1994.
Genetic variation and molecular evolution within the seventh-pandemic clone of Vibrio cholerae O1 and its relationship to other V. cholerae isolates were examined by studying 58 clinical isolates that were epidemiologically unassociated and isolated from patients in different countries over 62 years (1931 to 1993). The sample consisted of 45 isolates from the seventh cholera pandemic (1961 to the present), 3 from the sixth pandemic, 3 from sporadic El Tor outbreaks prior to the seventh pandemic, 2 from the U.S. Gulf Coast, and 5 O139 Bengal isolates. Ribotyping detected 11 polymorphic restriction sites within the seventh-pandemic isolates and showed major differences in ribotypes in comparison with sixth- and pre-seventh-pandemic isolates. O139 isolates were very similar to isolates from the start of the seventh pandemic, differing at only two sites. The majority of seventh-pandemic isolates fall into two groups, the first present from 1961 to the present and found only in Asia and the second arising in 1966 and spreading worldwide. Both groups underwent change over time, allowing a provisional estimate for the nucleotide substitution rate within the seventh pandemic clone.
通过研究58株临床分离株来检测霍乱弧菌O1第七次大流行克隆株的遗传变异和分子进化及其与其他霍乱弧菌分离株的关系，这些分离株在流行病学上无关联，是在62年（1931年至1993年）期间从不同国家的患者中分离得到的。样本包括45株来自第七次霍乱大流行（1961年至今）的分离株、3株来自第六次大流行的分离株、3株来自第七次大流行之前的散发性埃尔托型霍乱暴发的分离株、2株来自美国墨西哥湾沿岸的分离株以及5株O139孟加拉型分离株。核糖分型检测到第七次大流行分离株中有11个多态性限制性位点，并且与第六次大流行和第七次大流行之前的分离株相比，核糖型存在重大差异。O139分离株与第七次大流行开始时的分离株非常相似，仅在两个位点存在差异。大多数第七次大流行分离株分为两组，第一组从1961年至今存在，且仅在亚洲发现，第二组于1966年出现并传播至全球。两组均随时间发生了变化，从而可以对第七次大流行克隆株内的核苷酸替代率进行初步估计。
